Tag: oscillation and waves

Quizzes (19) Questions (170)

Questions Related to oscillation and waves

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

The oscillations about a systems equilibrium position that occur in the absence of an external excitation are 

  1. free vibrations

  2. damped vibrations

  3. natural vibrations

  4. None of these
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

The oscillations about a system of equilibrium position that occur in the absence of an external excitation are free vibrations or natural vibrations.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

A person drives the paddle ball by moving his finger up and down at a certain frequency. In this example he is causing

  1. a damped vibration

  2. a forced vibration

  3. a mechanical vibration

  4. a transnational vinration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A person drives the paddle ball by moving his finger up and down at a accelerating frequency. This is the example of force vibration as the motion of finger force to move paddle balls.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

Which of the following is/are examples of forced oscillation?

  1. Tuning a radio

  2. Pipe instrument

  3. Rotating machinery

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

(i) Tuning of Radio (ii) Pipe instrument (iii) Rotating machinery.

In all of the above cases system is exerted by an external force which causes its motion. So, are forced oscillation.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

A driven oscillator is acted upon by a force $F={ F } _{ 0 }sin\ \omega $. The amplitude of oscillation is given by $A=\frac { { F } _{ 0 } }{ \sqrt { a{ \omega  }^{ 2\  }  -b\omega \ +c }} $, the resonant angular frequency is

  1. $d\frac { a }{ b }$
  2. $\dfrac { 2a }{ b } $
  3. $\dfrac { b }{a } $
  4. $\dfrac { b }{ 2a } $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The driven force $ F= {F} _{0} \sin \omega t$

The amplitude of oscillation 
$A=\dfrac { { F } _{ 0 } }{ \sqrt { { a\omega  }^{ 2 }-b\omega +c }  } $
At resonance frequency A become maximum.So,
$\dfrac { dA }{ d\omega  } =0\ \Rightarrow { F } _{ 0 }\left( \dfrac { 2a\omega -b }{ \left( a{ \omega  }^{ 2 }-b\omega +1 \right)^{ \dfrac { 3 }{ 2 }}  }  \right) =0\ \Rightarrow \omega =\dfrac{b}{2a} \rightarrow$  
This is the resonence frequency.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

The oscillation of a body or system with its own natural frequency and under no external influence other than the impulse that initiated the motion

  1. Damped oscillation

  2. Free oscillation

  3. Impulsive oscillation

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Force vibration is a type at vibration in which a body is vibrate without any external influence and vibrates with its natural frequency. So, given statement describes a free vibrations.


Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

Motion of reciprocating pistons in engine is an example of

  1. Forced vibration

  2. Natural vibration

  3. Recursive vibration

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A motion of reciprocating pistons in an engine is an example of force vibration. In this case motion of the piston is governed by a pressure of a gas inside ignition of a chamber.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

The motion of a vehicle suspension system just after the vehicle encounters a pothole is an example of 

  1. natural vibration

  2. damped vibration

  3. forced vibration

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The motion of a vehicle suspension system just after the vehicle encounters a pothole is an example of natural vibration. When suspension system encounters a pothole it is disturbed from its equilibrium position after that an oscillatory motion generates inside it to take it back its initial position but there is no external force which maintains that oscillatory motion.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

Assertion : A child in a garden swing periodically presses his feet against the ground to maintain the oscillations.
Reason : Then all free oscillations eventually die out because of the ever present damping force.

  1. If both assertion and reason are true and reason is the correct explanation of assertion.

  2. If both assertion and reason are true and reason is not the correct explanation of assertion.

  3. If assertion is true but reason is false.

  4. If both assertion and reason are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The free oscillation of a body or system is due to its own natural frequency and under no external influence. But to carry out it continuously, the external impulse is needed. The child is doing this by pressing the ground.

Obviously, in the absence of such external impulse or force, free oscillations will die soon due to other negative forces i.e. damping forces.

Therefore assertion and reason both are correct and the reason is the correct explanation of assertion.

 

Option A is correct.

Multiple choice free, damped and forced oscillations free, forced and damped oscillations oscillations oscillation and waves physics

A linear harmonic oscillator of force constant $2 \times$10$^{6}$Nm$^{-1}$ and amplitude 0.01 m has a total mechanical energy of 160 J. Its

  1. maximum potential energy is 100 J

  2. maximum kinetic energy is 100 J

  3. maximum potential energy is 160 J

  4. minimum potential energy is zero.
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

As, we know total mechanical energy $=$ maximum potential energy

$\therefore \quad ATQ.T.E=160J\Rightarrow Max.P.E.=160J$
$\Rightarrow$  Statement (C) is correct.
Also, for maximum kinetic energy, we know,
$K.E.=\dfrac { 1 }{ 2 } K\left( { x } _{ m }^{ 2 } \right) $
where ${ x } _{ m }=\left( 0.01 \right) m\quad & \quad K=2\times { 10 }^{ 6 }{ Nm }^{ -1 }$
$\Rightarrow K.E.=\left( \dfrac { 1 }{ 2 }  \right) \left( 2\times { 1 }0^{ 6 } \right) { \left( 0.01 \right)  }^{ 2 }=100J$
$\Rightarrow$  Statement (B) is the correct answer.